Specification | Selection Basis

Releasing Flow Rate
  Under 200 tons 200-600 tons Over 600 tons
Ratio of overload pressure Small type Standard type Large Flow type Standard type
V▢06 V▢08 V▢10 V▢12 VA20
40 Ratio - - - - 96000
50 Ratio 15500 15500 - 39000 84000
70 Ratio 13000 13000 18000 31000 70000
90 Ratio 11500 11500 14500 27000 60000
Refer page
 

 

Type of Limit Switch
  During the Production When Overload Happening After overload
2: NO type OFF ON ON
6: NC type ON OFF OFF
 
Installation model

over 600 tonsover 600 tons

 
Circuit Control System

VA typeVS type

over 600 tonsover 600 tons

 
Specification & Parameter of Press

F: press rated capacity (tons)
S: stroke length(mm)
N: stroke per minute (SPM)
H: rated tonnage point(mm)
D: cylinder diameter (cm)
n: cylinder number (pc)
h: cylinder stroke (cm)
 
Calculation Formulas for Model Selection
A = (πD²/4) x n (cm²) cylinder area
P = F x 110% x 1000/A (kgf/cm²) hydraulic pressure setting of overload (VS model)
Pa = P/m (kgf/cm²) air pressure setting ov overload (VA model)
V = N√SH-H² /87.5 (cm/sec) drop speed of slide
Q = A x V (cm³/sec) releasing flow rate
L 4 x A x h(cm³) volume of oil tank

m:  ratio of overload hydraulic pressure

Releasing flow rate (Q) of overload protector, which you choose has to be more than of cylinder volume.
If releasing flow rate isn't enough, please use two sets of overload protector.

 
Example (model: VA (VS)08-7☐ ☐)
F = 160 tons   A = (π26²/4) x 1 = 531 (cm²)
S = 200 mm   P = 160 x 110% x 1000/531≒332(kgf/cm²)........VS model
N = 40 SPM   Pa = 332/70≒ 4.75 (kgf/cm²).......VA model
H = 6 mm   V = 40√200x6-6² /87.5= 15.6 (cm/sec)
D = 26 cm   Q = 531 x 15.6= 8284 (cm³/sec)
n = 1 pc   L 4 x 531 x 1 ≧ 2120(cm³)
h = 1 cm        
 
Note

1. Hydraulic pressure (P) and air pressure (Pa) of overload protector, should be choose as higher as possible.
     (Example: P=335 kgf/cm² or Pa=4.8 kgf/cm²)

2. Hydraulic piping size:

VA (VS)08-☐ ☐ ☐ - ☐ ☐ ☐ VA (VS)12-☐ ☐ ☐ - ☐ ☐ ☐
Size (I.D./O.D) Work pressure (maxi.) Size (I.D./O.D) Work pressure (maxi.)
12/18 mm 400 kgf/cm² 14/22 mm 400 kgf/cm²
13/18 mm 320 kgf/cm² 16/12 mm 300 kgf/cm²
14/18 mm 250 kgf/cm² 18/22 mm 200 kgf/cm²

3. Inside diameter of air piping must be more than 6 mm.

Specification | Selection Basis